Abstract: China’s economy is undergoing a transformation in recent years, how to promote high-quality economic development has become a concern of the government and academia. As an important support to motivate technology innovation and promote high-quality economic development, the role of technology finance input should not be ignored. From the perspective of the participants of technology finance input, this paper divides the technology finance input into government technology appropriation, enterprise R&D investment, and financial institution technology loan, and explores the mechanism of each participant’s technology finance input affecting the high-quality economic development. Based on this, the effect and mechanism of the impact of technology finance input on the high-quality economic development of each participant are examined empirically using the provincial panel data from 2004 to 2020 in China. This study finds that the technology finance input of all participants significantly contributes to high-quality economic development, and the promotion effect of enterprise R&D investment is the biggest, followed by government technology appropriation, and the promotion effect of financial institution technology loan is the smallest. There is a significant heterogeneity of innovation talent concentration and finance concentration in the impact of technology finance input on the high-quality economic development of each participant. The promotion effect of technology finance input on high-quality economic development is more significant in both high innovation talent concentration and low finance concentration areas. The mechanism test shows that the government technology appropriation and the financial institution technology loan mainly promote high-quality economic development through substantive innovation, while the enterprise R&D investment mainly promotes high-quality economic development through strategic innovation. These conclusions provide policy insights for China to further strengthen the supporting role of technology finance input and achieve high-quality economic development.